In preparing woven textile fabrics for marketing in the form of fabricated products, such as bed sheets or the like, or piece goods, such as garment fabrics, the selvage edges along the longitudinal side edge portions of the textile fabric and parallel with the warp yarns in the fabric must have an aesthetically pleasing appearance, while being durable to an accepted number of washings, i.e. up to about 50 washings for bed sheets and up to about 25 washings for apparel fabrics, without raveling of the yarns at the selvage edges. Also, if continuous lengths of the textile fabric are cut transversely and parallel with the filling yarns, the transverse cut edges must have the same characteristics.
Heretofore, with the use of normal shuttle-type looms, selvage edges of the acceptable type discussed above could be easily woven directly into the textile fabric as it is woven on the shuttle-type looms. However, with the recent advent of high speed looms, particularly, air jet looms, a fringed selvage is produced on one or both longitudinal side edge portions of the fabric by the loom which is undesirable from the standpoint of aesthetics in the marketable end products and often in finishing of the fabric after it is woven on the looms. While for some end products it is acceptable to some manufacturers to simply trim the fringe along the selvage edges, this procedure is not acceptable to others particularly when producing bed sheets and garment fabrics. Accordingly, such undesirable selvage must be cut off in predetermined widths and the cut side edges must be sealed to prevent raveling of the yarns at the cut edges. Also, when transverse cuts are made through the textile fabric, the cut edges must be sealed to prevent raveling of the yarns at such cut edges. This sealing has conventionally been performed by hemming of such cut edges with a sewing machine. However, such cutting and hemming operations, particularly along the entire longitudinal edges of the textile fabric, are by necessity time consuming and, thus, slow down further processing of the textile fabric following weaving on the looms.
With this problem in mind, applicants investigated a number of alternate apparatuses and processes which might be used for cutting woven textile fabric and particularly for cutting off predetermined widths of the undesirable selvages and sealing the cut edges to produce an aesthetically pleasing cut and sealed edge which had a preferable wash durability of at least 25 to 50 washings without significant raveling of the yarns at the cut and sealed edges.
The apparatuses and processes investigated for accomplishing the above included laser operations, hot wheel cutting and sealing, mechanical cutting and adhesive application, and ultrasonics. As a result of these investigations by applicants, lasers, hot wheel cutting and sealing, and mechanical cutting and adhesive application were determined to be unacceptable processes and apparatuses for accomplishing these purposes. The laser operation, while it produced a sharp cut edge, provided blackened edges and little, if any sealing which resulted in no durability to washing of the cut edges. Hot wheel cutting and sealing produced severe puckering and no durability to washings. The use of mechanical cutting and adhesive sealing produced generally stiff edges and resulted in other problems. Preliminary investigations by applicants with ultrasonic equipment and apparatus indicated that desired cutting and sealing probably could be performed which probably would provide an aesthetically acceptable cut and sealed edge and would likely produce the desired wash durability against raveling in the cut and sealed edge.
At the time of applicants' invention, ultrasonic slitting and sealing equipment was available from several manufacturers including Branson Sonic Power Company, Sonobond Ultrasonics and Cavitron Ultrasonics in the United States and F. Calemard and Cie of France. Commercial brochures of the ultrasonic slitting and sealing equipment of these companies indicated that this equipment was designed primarily for use with all plastic or thermoplastic materials including primarily nonwoven extruded sheet materials or 100% thermoplastic fiber woven material. However, these brochures did indicate that the equipment could be utilized to cut and seal woven textile fabric having blended yarns therein in which all of the fibers of the yarns were not necessarily thermoplastic, but only a substantial portion thereof were thermoplastic. Notwithstanding, to applicants' knowledge all of the applications or use of ultrasonic slitting and sealing equipment on such woven textile fabrics having blended yarns was for producing end products having a cut and sealed edge which did not require the high degree of wash durability against yarn raveling preferably of from about 25 to 50 washings as did the end products desired by applicants. Accordingly, woven textile fabrics of blended thermoplastic and non-thermoplastic fibers with ultrasonic cut and sealed edges having the characteristics discussed above did not exist to applicants' knowledge prior to the present invention.